US pharmaceutical company Merck & Co said on Wednesday that its four-valent human papillomavirus vaccine has been approved for men aged 9 to 26 by China's top drug regulator.

The vaccine that protects against four HPV strains is the first shot for males on the Chinese mainland. It was first authorized for use among females aged 9 to 45 in 2017 in the nation.

The majority of HPV infections are asymptomatic, but they are linked to a higher risk of cervical cancer among females and penile, anal and oropharyngeal cancers among males.

Qiao Youlin, a researcher from the School of Population Medicine and Public Health at Peking Union Medical College, said that globally, the prevalence of HPV infection among men is higher than that among women, but less attention has been paid to male infections.

International experts have called for delivering HPV vaccines to both genders to expand immunization coverage and better achieve herd immunity.